Howard Taylor Ricketts (1871–1910) was born in Findley, Ohio. He received an undergraduate degree in zoology from the University of Nebraska and then completed his medical degree at Northwestern University in 1898. After continuing his studies at Rush Medical College and in Europe, Ricketts became an associate professor of pathology at the University of Chicago in 1902. That same year, the state of Montana began funding medical research into the etiology of Rocky Mountain spotted fever. While this disease rarely claimed more than a dozen lives in a year, it was particularly virulent in Bitterroot Valley, an increasingly prosperous and influential community. After three years of research and surveys, however, scientists disagreed on its origin and its process of transmission.
Ricketts initiated a new study of spotted fever in 1906. By using laboratory animals, Ricketts was able to demonstrate that ticks transmitted the disease and this finding led to a public health campaign that targeted the elimination of ticks. Although Ricketts observed a very small bacillus, he was unable to isolate and culture the causal agent using contemporary laboratory techniques. Nonetheless, his work suggested that bacterial diseases could be biologically transmitted from pests to people. He published his findings in the Journal of the American Medical Association under the title "A Micro-Organism Which Apparently Has a Specific Relationship to Rocky Mountain Spotted Fever: A Preliminary Report" in 1909.
The following year a lack of funding prevented Ricketts from returning to Montana, and, instead, he traveled to Mexico City to study a disease that provided a similar puzzle, typhus fever. Ricketts again discovered that arthropods, in this case lice, carried the disease and transmitted it to humans. At the same time, he was also frustrated in his attempts to culture the bacillus. While conducting this study, Ricketts contracted typhus fever and died, but his belief that both diseases were due to microorganisms was proven in the next decade. The disease-causing genus of bacteria Rickettsia is named after Howard Ricketts.
Harden, V A. (1985). "Rocky Mountain Spotted Fever Research and the Development of the Insect Vector Theory, 1900–1930." Bulletin of the History of Medicine 59(4):449–466.
—— (1990). Rocky Mountain Spotted Fever: History of a Twentieth Century Disease. Baltimore, MD: Johns Hopkins University Press.